Chemokine is a series of families of small inflammatory cytokines having a strong chemotactic activity and being composed of about 70-120 amino acids, and is a chemotactic cytokine released from a wide variety of cells in order to lead various cells such as monocyte, macrophage, T cell, eosinophil, basophil, neutrophil and the like to the inflammatory site. The chemokine family was originally defined by 4 conserved cysteine residues in an amino acid sequence, namely, classified into two subfamilies of CXC-chemokine family and CC-chemokine family based on the configuration of the first cysteine pair (two residues) on the N terminal side. In the CXC-chemokine family including CXCL1, Mig, CX3CL1, IL-8, Gro-α, NAP-2, IP-10 and the like, these two cysteine residues are separated by one of the amino acid residues other than cysteine; on the other hand, in the CC-chemokine family including RANTES(CCL5), MCP-1(CCL2), MCP-2(CCL8), MCP-3(CCL7), MCP-4(CCL13), MIP-1α(CCL3), MIP-1β(CCL4), Eotaxin(CCL11), Eotaxin-2(CCL24), Eotaxin-3(CCL26), PARC(CCL18), TARC(CCL17), MDC(CCL22), LARC(CCL20), ELC(CCL19), SLC(CCL21), I-309(CCL1), TECK(CCL25), CTACK(CCL27), MEC(CCL28) and the like, these two cysteine residues are contiguous. Thereafter, the C chemokine family having, of the four cysteine residues originally present, only two cysteine residues corresponding to the second and the fourth residues from the N terminal side, and the CX3C chemokine family having a sequence having three amino acid residues different from cysteine between the first two cysteine residues on the N terminal side were found.
Ten kinds of receptors have been reported as the chemokine receptor that CC-chemokine family binds to. That is, CCR1 (alias, CKR1 or CC-CKR-1) bindable with MIP-1α, MIP-1β, MCP-3, RANTES and the like, CCR2A (alias, CKR2A or CC-CKR-2A) and CCR2B (alias, CKR2B or CC-CKR-2B) bindable with MCP-1, MCP-2, MCP-3, MCP-4 and the like, CCR3 (alias, CKR-3 or CC-CKR-3) bindable with Eotaxin, Eotaxin-2, RANTES, MCP-2, MCP-3 and the like, CCR4 (alias, CKR4 or CC-CKR-4) bindable with TARC, MDC and the like, CCR5 (alias, CKR-5 or CC-CKR-5) bindable with MIP-1α, RANTES, MIP-1β and the like, CCR6 (alias, GPRCY4) bindable with LARC and the like, CCR7 (alias, EBI-1) bindable with ELC, SLC and the like, CCR8 bindable with I-309 and the like, CCR9 (alias, GPR9-6) bindable with TECK and the like, and CCR10 bindable with CTACK, MEC and the like are known [Nature Reviews Immunology, 2002, vol. 2, page 106].
Chemokine receptors have different expression cells depending on the kind of the receptor. For example, CCR1 is expressed in various cells such as monocyte, T cell, mast cell, eosinophil, basophil and the like, and CCR2 is expressed in various cells such as dendritic cell, B cell, basophil, eosinophil, vascular endothelial cell, fibroblast, platelet, T cell and the like. On the other hand, some receptors are expressed only in some cells such as CCR3 expressed in eosinophils and basophil, and CCR9 expressed in T cells.
Since involvement of chemokine receptor in various diseases has been reported, a medicament modulating a chemokine receptor activity is expected to be a therapeutic drug for various diseases [Expert Opinion on Investigational Drugs, 2010, vol. 19, page 345]. Heretofore, plural chemokine receptor activity modulators have been used as therapeutic drugs. For example, it has been clarified that, when CD4+T cells are infected with HIV, HIV invades into the cells via CCR5, and therefore, CCR5 antagonist is used as a therapeutic drug for HIV infection. Also, as a medicament for mobilization of stem cells in autologous stem cell transplantation in patients with non-Hodgkin lymphoma and multiple myeloma, a combined use of an antagonist of CXCR4 which is a receptor of CXC-chemokine family with G-CSF has been approved. Besides these, CCR3 antagonist, CCR9 antagonist, antibody to CCR4 and the like are under clinical tests [Expert Opinion on Investigational Drugs, 2010, vol. 19, page 345].
As diseases involving a chemokine receptor, inflammatory diseases such as asthma, rhinitis, dermatitis, allergic disease and the like, immunoregulatory disorders and diseases, autoimmune diseases such as rheumatoid arthritis, lupus erythematosus, generalized scleroderma, Sjogren's syndrome, Celiac disease and the like, and the like are known [Current Opinion in Immunology, 2001, vol. 13, page 670]. Involvement of chemokine receptors such as CCR1; CCR2A; CCR2B; CCR3; CCR4; CCR5; CCR6; CCR7; CCR8; CCR9; CCR10; CXCR3 and CXCR4 which are receptors of CXC-chemokine family; and the like in the onset of these diseases has been reported. Among these, as a disease involving CCR4, CCR8, CCR9, CCR10 and the like, skin diseases and the like are known [Journal of Investigative Dermatology, 2009, vol. 129, page 2552].
As skin diseases involving a chemokine receptor, acne vulgaris, drug eruption, contact dermatitis, pollen dermatitis, urticaria, psoriasis, atopic dermatitis, Candida dermatitis, seborrheic dermatitis, eczema, Stevens-Johnson syndrome, toxic epidermal necrosis, erythema multiforme, pityriasis rosea, lichen planus, lichen pilaris (keratosis pilaris), herpes simplex, lupus erythematosus, keloid, scabies, generalized scleroderma and dermatitis as a side effect of anti-cancer agents and the like are known. In these skin diseases, various chemokines are highly expressed in the skin. For example, it is known that, in psoriasis, expression of chemokines such as MCP-1, RANTES, TARC, MDC, CTACK, CXCL1, Gro-α, IL-8, Mig, IP-10, CX3CL1 and the like increases in the dermatitis site and T cells and neutrophils infiltrate into the skin via CCR4; CCR6; CCR10; and CXCR1, CXCR2 and CXCR3, which are receptors of CXC chemokine family; and the like (non-patent document 1), in atopic dermatitis, expression of chemokine such as 1-309, MCP-1, MIP-1α, MIP-1β, RANTES, Eotaxin, MCP-4, PARC, LARC, MDC, Eotaxin-3, CTACK and the like increases in the dermatitis site and T cells, monocyte, eosinophils infiltrate into the skin via CCR1; CCR2A; CCR2B; CCR3; CCR4; CCR5; CCR6; CCR8; CCR10; CX3CR1 which is the receptor of CX3C chemokine family; and the like (non-patent document 2) and the like. Also, it has been reported that anti-CTACK antibody suppresses dermatitis in various dermatitis models and the like (for example, non-patent documents 3, 4, 5, 6 and the like). As a medicament that modulates chemokine receptor activity in skin diseases and the like in which these chemokine receptors are involved, pyrazolopyrimidine derivatives are known (patent document 12).
CCR10 is a chemokine receptor belonging to the C-C chemokine family [Genomics, 1994, vol. 23, page 609], and mainly expressed in the cells localized in the skin such as Cutaneous lymphocyte-associated antigen (CLA) positive skin-homing T cells, skin vascular endothelial cell, skin fibroblast, skin keratinocyte and the like. As a chemokine whose receptor is CCR10, two kinds of Cutaneous T-cell attracting chemokine (CTACK: alias CCL27) and Mucosae-associated epithelial chemokine (MEC: alias CCL28) are known. CCR10 and ligand thereof are said to be involved in the immunity of epithelial cells [Protein & Cell, 2012, vol. 3, page 571].
In recent years, involvement of CCR10 in atopic dermatitis has been reported. CTACK is selectively expressed in skin keratinocytes, and skin-homing CCR10 positive cells selectively migrate into CTACK. In patients with atopic dermatitis, expression of CTACK in the lesion skin is promoted, and in atopic dermatitis patients, the blood level of CTACK shows a positive correlation with the severity of dermatitis (non-patent document 7). Also, in the lesion skin of atopic dermatitis patients, localization of CCR10 positive T cells is found, and the CCR10 mRNA expression level of peripheral blood CD4 positive T cells of atopic dermatitis patients is higher than that of healthy adult (non-patent document 8). Furthermore, IL-22 is highly expressed in the skin lesion of atopic dermatitis patients, suppresses filaggrin production of the skin and is involved in the destruction of skin barrier. CCR10 is selectively expressed in Th22 cells that highly produce IL-22 (non-patent documents 9 and 10).
The role of CTACK and CCR10 in dermatitis has been studied by using mouse dermatitis model. When chronic contact dermatitis involving type 2 helper T cell is developed in keratinocyte selective CTACK highly expressing mouse, infiltration of CCR10 positive T cells in the skin tissue and skin tumentia significantly increase as compared to wild-type mouse (non-patent document 11).
On the other hand, as pyridone compounds, compounds represented by the following formulas (A), (B) (patent documents 1, 2) and the like are known as compounds having arylamino at the 4-position and monoalkylcarbamoyl at the 5-position, a compound represented by the following formula (C) (patent document 3) and the like are known as a compound having aryloxy at the 4-position and aliphatic heterocyclic carbonyl at the 5-position, a compound represented by the following formula (D) (patent document 4) and the like are known as a compound having dialkylcarbamoyl at the 5-position, a compound represented by the following formula (E) (patent document 5) and the like are known as a compound having monoalkylcarbamoyl at the 5-position, and a compound represented by the following formula (F) (patent document 6) and the like are known as a compound having monoarylcarbamoyl at the 5-position. Besides these, for example, various pyridone compounds represented by the following formulas (G)-(K) and the like are known (patent documents 7-11).
